1. Field of the Invention
The present invention relates to connecting devices and more particularly to such a device for reliably connecting a pair of cables.
2. Description of Related Art
A conventional cable connecting device is shown in FIGS. 10, 11 and 12. It comprises a male coupling 1, a female coupling 2, a male fastening element 3, a female fastening element 4, a plastic shield of first cable 5, a plastic shield of second cable 6, a first coupling 7, a second coupling 8, and a union 9. Each of above components will now be described in detail below.
The plastic shield of second cable 6 has a forward end inserted into the female coupling 2. The plastic shield of second cable 6 comprises two apertures 6C in the forward end for receiving the female fastening element 4 and thus connecting together conductors 6a of the second cable and the female fastening element 4. The female coupling 2 has outer peripheral ridges 2b in the rear end. The second coupling 8 has an inner thread 8a tapered toward the rear as seen from FIG. 10. Hence, a tight coupling between the second coupling 8 and the female coupling 2 is carried out as the outer thread 2b is inserted into the second coupling 8 for securing to the plastic shield of second cable 6. Also, the female coupling 2 has an outer thread 2c in the forward end.
The union 9 comprises an inner thread 9a put on the male coupling 1. The plastic shield of first cable 5 has a forward end inserted into the male coupling 1. The plastic shield of first cable 5 comprises two apertures 5C in the forward end for receiving the male fastening element 3 and thus connecting together conductors 5a of the first cable and the male fastening element 3. The male coupling 1 has an outer thread 1a in the rear end. The first coupling 7 has an inner thread 7a tapered toward the rear as seen from FIG. 10. The union 9 is secured around the outer thread 2c of the female coupling 2 and the female fastening element 4 are inserted into apertures 3a in the forward end of the male fastening element 3 for coupling. Hence, a tight coupling between the first coupling 7 and the male coupling 1 is carried out as the inner peripheral ridges 1b secured to the plastic shield of first cable 5. This completes a connection of cables.
However, the prior art cable connecting device suffered from several disadvantages. For example, a securing force of the inner peripheral ridges 1b exerted on the plastic shield of first cable 5 is vertical and not sufficient. Hence, such securing is not reliable. Further, a tensile strength of the cables is not sufficient in a practical use. Likewise, a securing force between the female coupling 2 and the plastic shield of second cable 6 is not reliable. Furthermore, the well-known cable connecting device consists of many loose parts (e.g., the male coupling 1, the female coupling 2, the male fastening element 3, the female fastening element 4, the plastic shield of first cable 5, the plastic shield of second cable 6, the first coupling 7, the second coupling 8, and the union 9) that have to be assembled by the user. Hence, it is expensive to produce and time consuming to assemble. Moreover, the prior art is not waterproof. In detail, water can penetrate through gaps between the inner peripheral ridges 1b of the male coupling 1 and the plastic shield of first cable 5. Also, moisture generated by the penetrated water will cause short circuit or rust in the male fastening element 3. This also occurs between the female coupling 2 and the plastic shield of second cable 6. In addition, the first coupling 7, the second coupling 8, and the union 9 are threaded parts. Hence, they are susceptible to being disengaged from the male coupling 1 and the female coupling 2. That is, the securing between the male coupling 1 and the female coupling 2 is not reliable. This in turn deteriorates the water penetration problem as well as significantly decreases the tensile strength of the cables. Thus improvement exists.
It is an object of the present invention to provide a device for connecting cables having the following advantages. At least one waterproof means is provided. This is advantageous over the prior art. An external force is applied in the same direction as that of a tensility of the invention. Hence, a tensile strength of the invention is advantageous over the prior art. A pair of terminals are provided for ease of tightly coupling together. The invention is designed to comply with a safety rule stipulated by the government. Hence, a coupling of a male coupling and a female coupling is reliable. This is best illustrated in second and third preferred embodiments in which a tool is required to disengage one from the other. This is also advantageous over the prior art. The invention has less constituent components so as to simplify an assembly and reduce a manufacturing cost. A simple, quick assembly is feasible. This is also advantageous over the prior art. A waterproof member is provided either between the male coupling and a first cable or between the female coupling and a second cable. Thus, three waterproof means are provided for enhancing a waterproofing between the male coupling and the first cable and between the female coupling and the second cable.
The above and other objects, features and advantages of the present invention will become apparent from the following detailed description taken with the accompanying drawings.